President Alexander Lukashenko of Belarus will launch military action against Ukraine if his country is attacked by even "one soldier."

"I'm ready to fight together with the Russians from the territory of Belarus in one case only: if so much as one soldier from (Ukraine) comes to our territory with a gun to kill my people," said Lukashenko.

Lukashenko made the comment Thursday in a press conference hosting foreign reporters at the Independence Palace in Minsk.

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"This applies to our other neighbors," Lukashenko added. "If they commit an aggression against Belarus, our response will be the most cruel. The most cruel!"

Lukashenko is the longest-sitting European president, holding the office since it was established in 1994 following the dissolution of the Soviet Union. Domestic and foreign opponents of the regime have criticized his successive electoral victories as fraudulent. 

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The government has arrested tens of thousands of political dissidents who question the legitimacy of the Belarusian government.

Belarus remains a strong ally of Russia and supports the invasion of Ukraine. However, the Belarusian government has repeated expressed that there is no intention to join the conflict.

Ukrainian forces are killing nearly 1,000 Russian troops every day, and they eliminated 5,000 troops in a single battle in late January, according to U.K. officials citing data from Ukraine.

Russian troops, including the elite 155th naval infantry, stormed the Ukrainian coal mining city Vuhledar near Dontesk in late January. Ukrainian forces repelled the offensive, however, and killed, injured or captured 5,000 Russian troops. 

Meanwhile, U.K. officials say the war is exacting a heavy toll on Russia, with 824 Russian troops dying each day, according to Ukrainian updates.

Fox News Digital's Anders Hagstrom contributed to this report.